1. Field Of The Invention
This invention relates to novel corrosion inhibitors and to hydrocarbon solutions containing them.
2. Description Of The Prior Art
Corrosion inhibitors are often added to hydrocarbon liquids in an attempt to curb or prevent rusting of the systems in which the hydrocarbons are stored, the systems in which the hydrocarbons are used, or both. Two hydrocarbons to which corrosion inhibitors are usually added are fuels and lubricating oils. Different qualities may be sought in corrosion inhibitors intended for use in lubricating oils versus corrosion inhibitors intended for use in fuels. Furthermore, concentrations will vary widely, it being likely that concentrations of inhibitors in lubricating oils will be much higher than concentrations of inhibitors in fuels.
Corrosion inhibitors used in fuels are primarily intended to prevent corrosion in storage tanks and pipelines. The corrosion problem in storage and pipeline systems usually stems from water contamination. One of the requirements demanded of corrosion inhibitors intended for use in fuel systems is that the inhibitor must be effective in very small quantities. That demand is made to avoid any adverse effects such as adding to the gum component of the fuel, etc., as well as to minimize costs. Another important requirement is that the corrosion inhibitor, in the amounts employed, must not act to emulsify water.
There is presently a need for a corrosion inhibitor for use in fuel storage tanks and pipelines where temperatures generally parallel outdoor ambient temperatures, maximum temperatures only occasionally exceeding about 100.degree. F. (38.degree. C). The corrosion inhibitor should be effective at low concentrations and should not emulsify undesirable amounts of water. The two-component, acid/acid corrosion inhibitor of this invention satisfies that need.
U.S. Pat. No. 2,632,695 discloses the use of polymerized C.sub.16 to 18 unsaturated monocarboxylic acids as rust inhibitors for mineral oil products such as gasoline, naphthas and fuel oils. This patent also teaches that the performance of corrosion inhibitors depends upon whether the hydrocarbon substrate is a lubricating oil or a nonlubricating hydrocarbon fraction, such as a fuel. Patentees make it clear that the problem to be solved when the hydrocarbon is a fuel is different from the problem to be solved when the hydrocarbon is a lubricating fraction of mineral oil. See especially in that regard: Column 1, lines 8 to 25, column 2, lines 20 to 28, and column 14, line 41 to column 15, line 32.
U.S. Pat. No. 2,631,979 discloses the use of polymerized linoleic acid as a rust inhibitor for oils and fuels. U.S. Pat. Nos. 2,124,628 and 2,741,597 disclose the use of alkenylsuccinic acids as antirust agents in lubricating oils. U.S. Pat. No. 3,208,945 discloses a combination of a polymerized linoleic acid and a monoalkenylsuccinic anhydride having 8 to 18 carbon atoms in the alkenyl group as an antirust agent in lubricating oils.
Comparisons have been made between polymerized monocarboxylic acid/monoalkenylsuccinic anhydride compositions, and polymerized monocarboxylic acid/monoalkenylsuccinic acid compositions of this invention. The comparative results, shown by Examples 5 and 6 versus Comparative Examples 7 and 8 support patentability of the compositions of this invention because of their unexpectedly superior corrosion inhibiting properties.